CVE-2026-10670: memory-safety in zephyrproject zephyr
The CONFIG_USERSPACE verification handler for the k_thread_name_copy() system call (z_vrfy_k_thread_name_copy() in kernel/thread.c) calls k_object_find() on the caller-supplied thread pointer and then dereferences the returned struct k_object without checking it for NULL. k_object_find() returns NULL whenever the supplied pointer is not a registered (static or dynamic) kernel object. The pre-fix guard tested thread == NULL instead of ko == NULL, so an unprivileged user-mode thread that invokes k_thread_name_copy() with any non-NULL but unregistered pointer (e.g. an arbitrary address) passes the NULL test, after which the verifier reads ko->type through a NULL pointer. Because the syscall verifier runs in supervisor mode, this NULL dereference is a kernel-mode fault that halts or reboots the system, allowing untrusted user code to crash the kernel across the userspace security boundary (denial of service). The marshaller passes the thread argument to the verifier without any prior K_SYSCALL_OBJ validation, so the bad pointer reaches the defect directly. The flaw affects builds with CONFIG_USERSPACE and CONFIG_THREAD_NAME enabled and has been present since the special-case lookup was introduced around v2.0.0; it is present in v4.4.0 and earlier. The fix changes the guard to check the k_object_find() return value (ko == NULL) before dereferencing it.
AI Analysis
Technical Summary
The vulnerability exists in the CONFIG_USERSPACE verification handler for the k_thread_name_copy() syscall in Zephyr's kernel. The verifier calls k_object_find() on a user-supplied thread pointer and dereferences the returned kernel object struct without verifying it is non-NULL. Previously, the code incorrectly checked if the original thread pointer was NULL rather than the kernel object pointer. Because k_object_find() returns NULL for unregistered pointers, this leads to a NULL pointer dereference in supervisor mode, causing a kernel fault and system crash. This allows unprivileged user-mode threads to cause denial of service by crashing the kernel. The flaw affects Zephyr versions from approximately 2.0.0 through 4.4.0 with CONFIG_USERSPACE and CONFIG_THREAD_NAME enabled. The fix involves adding a proper NULL check on the kernel object pointer before dereferencing it.
Potential Impact
The vulnerability allows an unprivileged user-mode thread to crash or reboot the system by triggering a kernel NULL pointer dereference in supervisor mode. This results in a denial of service across the userspace security boundary. There is no impact on confidentiality or integrity, only availability is affected.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. The fix involves changing the verification handler to check the return value of k_object_find() for NULL before dereferencing it. Until a patch is applied, avoid running untrusted user-mode code that can invoke k_thread_name_copy() with arbitrary pointers. Monitor vendor channels for an official fix.
CVE-2026-10670: memory-safety in zephyrproject zephyr
Description
The CONFIG_USERSPACE verification handler for the k_thread_name_copy() system call (z_vrfy_k_thread_name_copy() in kernel/thread.c) calls k_object_find() on the caller-supplied thread pointer and then dereferences the returned struct k_object without checking it for NULL. k_object_find() returns NULL whenever the supplied pointer is not a registered (static or dynamic) kernel object. The pre-fix guard tested thread == NULL instead of ko == NULL, so an unprivileged user-mode thread that invokes k_thread_name_copy() with any non-NULL but unregistered pointer (e.g. an arbitrary address) passes the NULL test, after which the verifier reads ko->type through a NULL pointer. Because the syscall verifier runs in supervisor mode, this NULL dereference is a kernel-mode fault that halts or reboots the system, allowing untrusted user code to crash the kernel across the userspace security boundary (denial of service). The marshaller passes the thread argument to the verifier without any prior K_SYSCALL_OBJ validation, so the bad pointer reaches the defect directly. The flaw affects builds with CONFIG_USERSPACE and CONFIG_THREAD_NAME enabled and has been present since the special-case lookup was introduced around v2.0.0; it is present in v4.4.0 and earlier. The fix changes the guard to check the k_object_find() return value (ko == NULL) before dereferencing it.
CVSS v3.1
Score 5.5medium
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability exists in the CONFIG_USERSPACE verification handler for the k_thread_name_copy() syscall in Zephyr's kernel. The verifier calls k_object_find() on a user-supplied thread pointer and dereferences the returned kernel object struct without verifying it is non-NULL. Previously, the code incorrectly checked if the original thread pointer was NULL rather than the kernel object pointer. Because k_object_find() returns NULL for unregistered pointers, this leads to a NULL pointer dereference in supervisor mode, causing a kernel fault and system crash. This allows unprivileged user-mode threads to cause denial of service by crashing the kernel. The flaw affects Zephyr versions from approximately 2.0.0 through 4.4.0 with CONFIG_USERSPACE and CONFIG_THREAD_NAME enabled. The fix involves adding a proper NULL check on the kernel object pointer before dereferencing it.
Potential Impact
The vulnerability allows an unprivileged user-mode thread to crash or reboot the system by triggering a kernel NULL pointer dereference in supervisor mode. This results in a denial of service across the userspace security boundary. There is no impact on confidentiality or integrity, only availability is affected.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. The fix involves changing the verification handler to check the return value of k_object_find() for NULL before dereferencing it. Until a patch is applied, avoid running untrusted user-mode code that can invoke k_thread_name_copy() with arbitrary pointers. Monitor vendor channels for an official fix.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- zephyr
- Date Reserved
- 2026-06-02T15:25:33.216Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a56533f68715ace43bba7c3
Added to database: 07/14/2026, 15:18:23 UTC
Last enriched: 08/07/2026, 13:10:59 UTC
Last updated: 08/24/2026, 22:52:08 UTC
Views: 69
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